Hi! I had a connection problem while i was running:
tectonic -X build
The downloading of some files went wrong, and now i get this error message:
error: hyph-de-1996.tex:12985: Bad \patterns.
error: halted on potentially-recoverable error as specified.
Since this was a downloading error, i think i can fix it by starting all the downloads from scratch…but the “build” command just won’t start over. How can i solve this? Maybe ereasing the cached files and running “-X build” again?
Ok, i succeded, not thanks to your help…
I’ll assume you were busy.
So, i ereased all the cache files and the files of the new document i just had created. I ran
tectonic -X build
again, and this time the .pdf document was successfully created
Listen here, you @Simon_Flavio_Ibanez, if you expect 24/7 support from volunteers, please go somewhere else and please use expensive software and pay tons of money for support engineers to help you. There are quite a few companies willing to accept your money, I’m sure.
All good, thanks for sharing the solution you found 
Could someone say where the tectonic cache files are located? Thanks!
Thanks @PHPirates . So just for future reference I copy the cache paths here:
$HOME/.cache/Tectonic
~/Library/Caches/Tectonic
%LOCALAPPDATA%/TectonicProject/Tectonic